This principle applies also in the matter of colour.  Greater contrasts and variety of colour may be indulged in where the middle range only of tones is used, and where there is little tone contrast, than where there is great contrast.  In other words, you cannot with much hope of success have strong contrasts of colour and strong contrasts of tone in the same picture:  it is too violent.

If you have strong contrasts of colour, the contrasts of tone between them must be small.  The Japanese and Chinese often make the most successful use of violent contrasts of colour by being careful that they shall be of the same tone value.

And again, where you have strong contrasts of tone, such as Rembrandt was fond of, you cannot successfully have strong contrasts of colour as well.  Reynolds, who was fond both of colour and strong tone contrast, had to compromise, as he tells us in his lectures, by making the shadows all the same brown colour, to keep a harmony in his work.

[Illustration:  Plate XLVI.

OLYMPIA.  MANET (Louvre)

A further development of the composition formula illustrated by Correggio’s “Venus”.  Added force is given by lighting with low direct light elimination half-tones.

Photo Neurdein]

There is some analogy between straight lines and flat tones, and curved lines and gradated tones.  And a great deal that was said about the rhythmic significance of these lines will apply equally well here.  What was said about long vertical and horizontal lines conveying a look of repose and touching the serious emotional notes, can be said of large flat tones.  The feeling of infinity suggested by a wide blue sky without a cloud, seen above a wide bare plain, is an obvious instance of this.  And for the same harmonic cause, a calm evening has so peaceful and infinite an expression.  The waning light darkens the land and increases the contrast between it and the sky, with the result that all the landscape towards the west is reduced to practically one dark tone, cutting sharply against the wide light of the sky.

And the graceful charm of curved lines swinging in harmonious rhythm through a composition has its analogy in gradated tones.  Watteau and Gainsborough, those masters of charm, knew this, and in their most alluring compositions the tone-music is founded on a principle of tone-gradations, swinging and interlacing with each other in harmonious rhythm throughout the composition.  Large, flat tones, with their more thoughtful associations are out of place here, and are seldom if ever used.  In their work we see a world where the saddening influences of profound thought and its expression are far away.  No deeper notes are allowed to mar the gaiety of this holiday world.  Watteau created a dream country of his own, in which a tired humanity has delighted ever since, in which all serious thoughts are far away and the mind takes refreshment in the contemplation of delightful things.  And a great deal of this charm is due to the pretty play from a crescendo to a diminuendo in the tone values on which his compositions are based—­so far removed from the simple structure of flat masses to which more primitive and austere art owes its power.